1. Technical Field
This invention relates generally to styluses, and more particularly to styluses configured for operation with touch-sensitive user interfaces.
2. Background Art
Touch-sensitive devices, such as smart phones, portable digital assistants, and tablet-style computers, are becoming increasingly popular. While electronic computing devices of the past traditionally were manufactured with numeric keypads or QWERTY keyboards, an increasing number of devices are being manufactured today exclusively with touch-sensitive screens and touchpads.
Capacitive touch-sensitive devices generally work by emitting a periodic waveform, such as a square wave or sine wave. When an object, like a user's finger for example, comes in close proximity with the surface of the touch-sensitive device, the object disturbs electric field lines between the periodic waveform generator and receptor electrodes. A sensing circuit can detect this distortion as user input.
Touch-sensitive devices are convenient in that a wide variety of “virtual” keypad configurations can be presented to a user. Touch-sensitive devices have physical limitations due to the width of a user's finger, which can be wider than the various touch-sensitive targets presented on the touch-sensitive device. Accordingly, the granularity with which small objects can be selected can be limited by the surface area of the user's finger. Said differently, a user will find it difficult to accurately select “touchable objects” on a touch-sensitive device must that are spaced closer than, or have a size smaller than, the size of a fingertip.
It would be desirable to create alternate ways of interfacing with touch-sensitive devices, where the alternate ways allow for finer granularity of selection, thereby enhancing the user experience.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.